In order to form color photographic images, a photographic material containing three kinds of photographic color couplers of yellow, magenta and cyan incorporated into three light-sensitive layers thereof having spectral sensitivities different from each other, respectively is exposed imagewise and then processed with a color developing solution containing a color developing agent. In this process, the couplers react with the oxidation products of aromatic primary amine developing agents to yield colored dyes.
In general, the standard steps of processing silver halide color photographic materials are composed of a color development step for forming color images, a desilvering step for removing developed silver and undeveloped silver, and a water washing step and/or an image stabilizing step.
The desilvering step for removing developed silver and silver halide described above comprises reoxidation of developed silver with an oxidizing agent and fixation using a silver halide solubilizing agent. The step can be conducted by successive two steps separately employing a bleaching solution, or by one step using a single solution containing both a bleaching agent and a fixing agent. The latter solution is ordinarily called a bleach-fixing solution or a blixing solution. While it is known that various oxidizing agents can be employed as the silver oxidizing agents in the bleaching solution or bleach-fixing solution described above, a metal complex salt of an organic acid, for example, a ferric complex salt of ethylenediaminetetracetic acid is usually used in view of low toxicity and environmental safety.
However, when the ferric complex salt described above is used as the bleaching agent for color photography, a cyan dye image having a sufficient density can not be obtained in some cases. This phenomenon is generally recognized as reduction discoloration resulted from conversion of the cyan dye to its leuco-body in the bleaching or bleach-fixing solution (hereinafter referred to as blix discoloration sometimes). In U.S. Pat. No. 4,591,548, it is pointed out that the conversion of the cyan dye to its leuco-body is caused by the presence of ferrous ions in the bleaching solution or bleach-fixing solution.
On the other hand, reduction of processing time has been hitherto sought. Recently, however, necessity for shortening the processing time increases more and more because of requirements on reduction of the period to finish, simplification of laboratory work, and miniaturization and simple operation of the processing system for small scale laborations which are designated so-called mini-labs.
The reduction of processing time for the color development step can be achieved by using a coupler having a high coupling speed, using a silver halide emulsion having a high developing speed, using a color developing solution having a high developing activity, using a color developing solution of high temperature or an appropriate combination thereof.
For the reduction of processing time for the desilvering step, decreasing a pH of the bleaching solution or bleach-fixing solution is effective. However, the decreasing a pH of the bleaching solution or bleach-fixing solution is accompanied with the problem in that the blix discoloration of cyan dye described above is accelerated.
In order to overcome the blix discoloration of cyan dye, various proposals have been made. For instance, the variation of concentrations or compositions of the bleaching solution or bleach-fixing solution is described to solve the problem, for example, in U.S. Pat. No. 3,706,561. In U.S. Pat. No. 4,366,233, to reduce the total amount of coated silver in layers positioned under the cyan dye forming layer of color photographic material is proposed. The addition of various compounds to the processing solution is described in U.S. Pat. No. 3,820,997. Also, the addition of a water-soluble ionic compound containing a polyvalent element to the bleach-fixing solution is proposed in U.S. Pat. No. 3,773,510.
In U.S. Pat. Nos. 4,151,680, 4,374,922 and 4,591,546, a group of cyan couplers preferred to solve the above described problem are described. Further, in JP-A-63-316857 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), the use of certain hydroquinone or quinone derivatives is described.
However, these known methods only have an insufficient effect, or have other problems in that the photographic properties, for example, image preservability are damaged and in that a load for waste solution treatment increases, although some effects are found.
Attempts to overcome the blix discoloration of cyan dye using a polymer latex has been made. Specifically, the use of a polymer latex having an alkoxyalkyl group in its side chain in order to prevent the conversion of cyan dye to its leuco-body is described, for example, in JP-A-64-52136 and JP-A-2-289840. However, the effect of such a polymer latex is still insufficient, and there is a problem to be solved in its property in case of conducting the color development processing in a short time. Further, the polymer latex is poor in its dispersion stability. Neither the specific polymer latex having such a high acid content as in the present invention nor its superior effect is described in these patents.
Therefore, a technique which has a large effect on preventing the blix discoloration of cyan dye and which is not accompanied with the above described problems is desired.
On the other hand, a polymer latex copolymerized with a monomer having a -COOH group is known in the field of photographic light-sensitive material. For example, in U.S. Pat. No. 3,287,289, a copolymer latex such as one of n-butyl acrylate and an acrylic acid or methacrylic acid is described. However, there is no disclosure that among the hitherto known polymer latexes, those having a high acid content are particularly effective to prevent the blix discoloration of cyan dye formed from a cyan coupler.